This core will provide expertise in the production and use of cDNA and oligonucleotide microarrays and the bioinformatics support required for data storage and analysis. The investigator provides the core laboratory with a minimum of 10 micrograms of total RNA from control and test cell samples; core personnel produce the target RNA, the microarrays, the hybridization, the image analysis, and preliminary data analysis, eDNA arrays are produced by printing PCR products from IMAGE consortium eDNA clones onto glass microscope slides using a commercial 3-axis robotic arrayer. Target total RNA is prepared by RT-PCR using oligo-dT and random primers in the presence of aminoallyl-dUYP. The eDNA is dye-labeled by coupling NHS-ester Cy3 or Cy5 dyes to free amines. The labeled cDNA is hybridized to the microarray in slide chanbers or in a GeneYAC hybridization workstation and scanned using a scanning laser confocal microscope (GSI Lumonics or Axon). The image data files are analyzed using GenePix software (Axon) and the data files archived to a server for simple retrieval using a Web-based database query tool (HCWebFetch). Subsequent analysis can be conducted using a range of microarray analysis software. The laboratory presently has about 85,000 mouse and human eDNA clones and are currently producing arrays with >9,000 features/slide. Samples may also be submitted to the core for analysis on Affymetrix GeneChip microarrays. The core has two complete Affymetrix instrumentation systems and all relevant GeneChips in stock for immediate use. Finally, the core has substantial bioinformatics resources in terms of computational hardware, expertise, and software/database resources. These resources include expert staff, a High Performance Computing Facility, Vector NTI, GenoMax (Sequence Analysis, Gene Expression, and 3D Modeling modules), Affymetrix LIMS system, Spotfire DecisionSite, and many other applications suitable for sequence and gene expression analysis. This element of the core is critical to the successful use and evaluation of DNA mieroarray experiments.